Will this diffuser scrape on speed bumps or steep driveways?

The diffuser extends below the factory bumper line, so approach angles matter on inclines and steep driveways. Verify your vehicle's current ride height and clearance before installation. Most owners adjust their line of approach when needed, but the extension is intentional for the aero look — this is not a low-clearance part.

Does this diffuser provide actual downforce, or is it cosmetic?

This is a styling diffuser — it visually mimics functional aero and works best as part of a complete rear aero package (splitters, wings, or spoilers). Standalone, it adds visual aggression and underbody flow lines. If you're targeting real high-speed downforce, you'll want to pair it with other aero elements.

What fasteners do I need to bolt this to my bumper?

The diffuser assembly does not include mounting hardware. Before purchasing fasteners, confirm your factory bumper hole locations and spacing — this ensures compatibility without drilling. Metric bolts and plastic clips work for most rear diffuser installations; reference your vehicle's service manual or consult the factory bumper assembly diagram to identify the correct fastener types and torque specs.